tree chop

Im curious of how to implement something. I have a 3d tree model with rigidbody physics, and when a player comes up and he has a 3d model of an axe attached to him and he left clicks, it plays a swing animation. Then if that 3d model intersects with the tree model, it registers as a hit of some sort. Then after 3 registered hits the tree has a force applied to it that pushes it down to the ground. How would I implement this?

collision sensor -> propertry actuator (counts add +1 to property hit)

property hit >=3 -> fall down (however you do that)